How to distinguish between Cygwin and Windows platforms ?

[Timothy Madden]

Hello

DejaGnu documentation says windows programs can be tested using Cygwin. 
However Cygwin is a platform in itself, which is different than native 
Windows, and some programs have specific Cygwin and Windows builds. Even 
without specific versions, some programs like vim and cmd.exe behave 
differently when run from cygwin than from Windows Explorer directly, or 
from the 'Run' window.

Is there a way to make sure my program will behave no different than 
expected for Windows, when my tests run from cygwin ? Is there a way to 
distinguish between cygwin and windows, as different targets ?

Also I see dejagnu reports 'unix' as the target when running from 
cygwin, which is the same as from my Linux machine. Is there a way to 
configure my tests so dejagnu detects the right platform ? So my tests 
can then adapt accordingly ?

Do I always need to rely on autoconf and automake to provide the target 
on the runtest command line ?

Thank you,
Timothy Madden